Sequel one_to_one association - ruby

Question

Referencing Sequel's docs I've set up a one_to_one association between a Position and a Company.
class Position < Sequel::Model
one_to_one :company
end
class Company < Sequel::Model
many_to_one :position
end
When I try to get a company through a position I get nil, although I can find the company with a direct Sequel query.
p = Position.first #=> #<Position #values={:id=>1}>
p.company #=> nil
Company.where(position_id: p.id).first #=> #<Company #values={:id=>1, position_id: 1}>

Answer 1

You look confused about the relations or the schema. Unless you have a very specific business case, a company has many positions, which makes one-to-many relation and many positions can belong to one company, which makes many-to-one.
Here's how I see it:
require 'sqlite3'
require 'sequel'
DB = Sequel.connect('sqlite://companies')
DB.create_table :companies do
primary_key :id
String :name
end
DB[:companies].insert(name: 'Acme')
DB.create_table :positions do
primary_key :id
String :name
foreign_key :company_id, :companies
end
DB[:positions].insert(name: 'CEO', company_id: DB[:companies].first[:id])
DB[:positions].insert(name: 'CTO', company_id: DB[:companies].first[:id])
class Company < Sequel::Model
one_to_many :positions
end
class Position < Sequel::Model
many_to_one :company
end
p Company.first.positions
# [#<Position #values={:id=>1, :name=>"CEO", :company_id=>1}>, #<Position #values={:id=>2, :name=>"CTO", :company_id=>1}>]
p Position.first.company
# #<Company #values={:id=>1, :name=>"Acme"}>

Answer 2

I can get your associations to work:
require 'sequel'
DB = Sequel.connect('sqlite://test.db')
unless DB.table_exists? (:positions)
DB.create_table :positions do
primary_key :id
string :name
foreign_key :company_id
end
end
unless DB.table_exists?(:companies)
DB.create_table :companies do
primary_key :id
string :name
foreign_key :position_id
end
end
class Position < Sequel::Model
one_to_one :company
end
class Company < Sequel::Model
many_to_one :position
end
ford = Company.create(name: "Ford")
vw = Company.create(name: "VW")
accountant.company = ford
p accountant.company #=> #<Company #values={:id=>53, :name=>"Ford", :position_id=>35}>
puts accountant.id #=> 35
accountant.add_company(vw) #=> undefined method `add_company' for #<Position...
I'll add that the Sequel docs for associations are terrible. They need to include a complete example--including how to create the objects so that they are associated with each other.